DNA stuck in wells!
SerAln at yahoo.com
Fri Oct 25 08:14:43 EST 2002
Searching the archives of this group, I found a post from Jim Kami (200'/02/18,
replying one of my posts) pointing to this paper:
Benore-Parsons, Marilee; Ayoub, Melissa A.. Presence of RNase A causes aberrant
DNA band shifts. Biotechniques, v.23, n.1, 1997.:128-131.
Abstract: RNase A, which is routinely added during DNA purification to
contaminating RNA, causes shifting of DNA bands in agarose gets. DNA band sizes
gels increase as much as 10%-20% when RNase A is present. The low concentrations
of RNase A
typically used to purify DNA cause shifting of select DNA bands, in contrast to
concentrations of RNase A where all bands are shifted and smeared The binding of
RNase A to
the DNA is specific and the degree of the shift varies; not all DNA bands are
the deviation is more pronounced in certain buffers. Other proteins, such as
albumin or proteinase K, do not induce DNA band shift, suggesting the interaction is
specific. The binding of RNase A to DNA is reversible. The formation of
may affect experiments involving DNA:protein interactions such as gel shift,
filter binding assays. Researchers performing DNA characterization from miniprep
should be aware that RNase may cause the apparent sizes of DNA fragments to be
obscure the presence of very small cloned fragments.
(sorry for the line wrapping)
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